1. Field of the Invention
The present invention is directed to a wheelchair lift. More specifically, the present invention is directed to a wheelchair lift with interlocks that promote proper operation. The present invention is also directed towards a wheelchair lift which requires a lower peak force for operation.
2. State of the Art
Wheelchair lifts raise and lower a wheelchair and/or passenger to and from vehicles. Wheelchair lifts are typically mounted in a doorway of a vehicle with a lift mechanism and have a platform that raises and lowers the wheelchair and/or passenger between the ground and the vehicle. A common wheelchair lift design uses a mounting structure comprising a parallelogram design having two sets of lift arms arranged in a parallelogram or near-parallelogram arrangement on either side of the platform. Other designs may include mounting structures having sliding arrangements such as where the platform is horizontally stowed adjacent to the vehicle bed and slid-out to a raising and lowering position.
Wheelchair lifts may use hydraulic actuators to provide the lifting force to move the platform. In certain situations, the use of electric actuators may provide certain features which are desirable to wheelchair lifts. For example, electric actuators may provide variable speed control. However, an electric actuator of a given force rating will cost more than a hydraulic actuator of the same force rating.
What is needed is a wheelchair lift with interlocks that promote proper operation. What is also needed is a wheelchair lift which requires a lower peak force for operation, to permit the practical use of electric actuators.